a. Field of the Invention
This invention relates to fabrics suitable for use in making sandbags and methods for making the same.
b. Description of the Prior Art
A fabric to be used in making sandbags must have several characteristics. It must not be degraded to any significant extent by sunlight. It must have a sufficiently close weave that sand or silt cannot leak or be washed from the bag by the action of water. Further, the fabric should have a relatively high strength.
It is known to make sandbag fabrics from low denier acrylic or modacrylic fibers, these fibers having an excellent resistance to sunlight. It is relatively easy, using fibers having a denier per filament of less than 5, to make sandbag fabric which is resistant to sunlight and which will retain either sand or clay. Conventionally, a sizing is applied to these yarns and the yarns are then woven into a fabric. Unfortunately, this fabric has several disadvantages. One disadvantage is the fact that size must be removed from the fabric before the fabric is used in order to prevent the formation of mildew and mold on the bag. Another disadvantage is that the use of the small denier per filament fibers results in a sandbag fabric which is easily cut or torn on construction sites and which does not have the outdoor durability that the bag would have if fibers of a greater denier were used.
If one attempts to make a sandbag fabric from staple fibers have a higher denier per filament, for example, 10 to 15 dpf, he encounters severe problems in weaving the yarn into the fabric. If no size is applied to the yarn prior to weaving, the hairiness or fuzziness of the yarn causes excessive down time on the weaving machine, resulting in a weaving efficiency which is probably less than about 40%. This is because the higher denier fibers are much stiffer, so that the yarn will not readily pass through the weaving machine. No improvement is seen when a size is applied to the yarns prior to weaving, since a warp made from the yarns exits from the slasher in almost the form of a solid bonded sheet. Separating the individual ends from this sheet causes even greater hairiness.
In the present invention, fibers of larger denier are used without sizing and with an increased weaving efficiency to make an improved fabric for use in making sandbags.